The present invention relates to a method and apparatus for positioning and drawing a pipe and more particularly to a method and apparatus for systematically positioning a large pipe, generally placed in a trench and subsequently covered with earth, and for pulling the pipe into engagement with another pipe already suitably located in the trench.
Underground pipelines are used for many purposes today. For example, underground pipes may be used for transmitting fluids such as fluid fossil fuel products, drinking water, sewage water, and miscellaneous waste products. Furthermore, underground pipes may be used for protecting buried electrical cables or fiber optic cables. Since these pipelines are numerous and increasing in number, and since existing pipelines require occasional replacement of pipe sections, an efficient and inexpensive method and apparatus for positioning pipes added to a pipeline is greatly needed.
Several different approaches have been tried in the past for setting and drawing pipes, and particularly pipes of large diameter. Many of these devices use external alignment and pipe positioning apparatus. For example, in U.S. Pat. No. 4,130,204 to Packard, a mobile land vehicle for laying successive pipe sections is disclosed. The device in Pickard includes a frame having a front and rear end and ground engaging support structure for the frame operative to support and advance the frame from and forwardly over the ground. The frame includes longitudinally spaced front and rear support structures supported therefrom and projecting outwardly from one side of the vehicle at points spaced therealong. The support structures each include pipe section engaging structures for engaging and supporting longitudinally spaced portions of a pipe section extending therebetween. The support structures each include structural components operative to adjustably position vertically and laterally the corresponding pipe section engaging structure relative to the frame of the vehicle.
Other examples of external apparatus for pulling and positioning pipes are found in U.S. Pat. Nos. 3,036,372 to Vigneron; U.S. Pat. No. 3,364,555 to Swink; U.S. Pat. No. 3,561,615 to Forsberg; U.S. Pat. No. 3,688,378 to Garvey; U.S. Pat. No. 3,710,427 to Doty; U.S. Pat. No. 3,840,968 to Mason; U.S. Pat. No. 4,039,087 to Sandvick, Sr.; U.S. Pat. No. 4,062,456 to Birdwell; U.S. Pat. No. 4,076,130 to Sumner; U.S. Pat. No. 4,218,158 to Tesson; and U.S. Pat. No. 4,253,779 to Grognu. The disadvantage of many of these devices is that they are often large and expensive. Many of them, including Pickard described above, often require two operators or an operator and an observer for proper operation. Furthermore, with many of these devices, at least a portion of the positioning must be done by another device, such as a backhoe machine. This increases the expense of using these devices, both in terms of equipment and in terms of manpower since the backhoe machine is not available for digging a trench while it is being used to lay and set pipes.
Alternatively, as shown in U.S. Pat. No. 4,107,317 to Bifani et al., a crane must be provided for initially positioning the pipe. This ties up extra personnel and requires additional, expensive equipment.
Still another solution which has been proposed for laying heavy pipe is shown in U.S. Pat. No. 3,958,704 to Wire et al. In Wire, a pipe carrying and laying attachment for heavy construction equipment, such as backhoes, excavation shovels and the like is provided. A support frame including a plurality of radially extending arms projecting therefrom, the terminal ends of the arms carrying support shoes, is adapted for fitting into the heavy pipe. Attachment permits the equipment to be used to lower the pipe for correct placement in a trench. Again, as described above, this method of laying pipe is inefficient since a rather large piece of equipment must be provided just for the purpose of positioning the pipe.
An alternate method for pulling pipe sections together has been described in the prior art involving a pulling device disposed within the pipes being joined. For example, U.S. Pat. No. 3,833,966 to Hubbard et al., teaches a method and machine for aligning and joining pipes wherein the machine is disposed within the pipe that is laid. Hubbard includes a mechanism that is extensible into the spigot end to be laid, the mechanism including rollers that are brought to abutting relationship with the shoulder at the spigot end of the pipe to be laid. The machine draws the spigot end of the pipe to be laid into sealing relationship with the bell of the pipe that was previously laid. Other examples of internally disposed pipe pulling apparatus may be found in U.S. Pat. Nos. 3,469,298, 3,486,214, 3,599,315, and 4,209,269. For each of these devices, the problem remains that the initial positioning of the pipe being added to the pipeline must be fairly accurate prior to the initiation of the pulling operation. Therefore, one of the above described positioning methods must still be used in conjunction with these pulling devices. Therefore, while these pulling devices more accurately position and interconnect the pipes of a pipeline, the need for the additional equipment continues to tie up both the additional equipment and the additional personnel during the pipe laying process.
Furthermore, once a pipe section is connected to an existing pipeline, dirt or aggregate material is backfilled into the trench around the newly added pipe. This operation can often result in movement of the newly added pipe relative to the pipeline, partially undoing the work done by the above described positioning and pulling devices. None of the prior art devices provides a way to prevent motion of the pipe during the backfilling operation.
What is needed, therefore, is an apparatus which may be used to accurately position a pipe added to a pipeline relative to the existing pipeline and to draw the new pipe into interconnection with the existing pipeline inexpensively and efficiently. Furthermore, what is needed is an apparatus which will secure the newly added pipeline in position during a backfilling operation.